scholarly journals ESTIMATION OF AMOUNT CHANGING OF LOCAL AERODYNAMIC RESISTANCE OF ELEMENTS OF VENTILATION SYSTEM OF MINE AT REVERSING BEHAVIOR OF VENTILATION SYSTEM

2019 ◽  
Vol 2 (4) ◽  
pp. 212-219
Author(s):  
Stanislav Pavlov

In the work study results of influence of typical working junction angle on amount changing of local aerodynamic resistances when air flows in different directions is represented. Using finite-element software, aerodynamic parameters of elements of mine ventilation network is obtained and is compared with analytical calculations Interinfluence local aerodynamic resistances located at ventilation network consecutively in normal and reversing behavior is discovered. It allows to increase accuracy of calculation of mine ventilation network at emergency ventilation operation.

2013 ◽  
Vol 423-426 ◽  
pp. 2291-2296
Author(s):  
Wei Wei Ye ◽  
Xian Ping Xie ◽  
Meng Wei Han ◽  
Shi Yun Luo ◽  
Zhen Li ◽  
...  

Selecting the optimal air regulation scheme of mine ventilation network, the essence is to choose the network a most optimal tree and obtain the corresponding optimal cosine tree combination program.Due to a synthetic consideration of the influence of production.Management economy and other aspects on the tree selection,the air flow regulating and controlling system made by the authors is optimum It is satisfactory to use the model for the north part ventilation system of Laochang tin mine of Yunnan tin Industrial crop. It is of practical significance to combine organically air flow regulating and controlling system with mine ventilation system.


2014 ◽  
Vol 59 (2) ◽  
pp. 381-394
Author(s):  
Haoran Zhang ◽  
Lluis Sanmiquel Pera ◽  
Vintro Sanchez Carla ◽  
Yaojiang Zhao

Abstract For the purpose of fully and systematically observe, research and optimize the U-sharp ventilation system in Vilafruns mine, a simulation model based on the principles of geometric, kinematic and dynamic similarity is established in the simulation laboratory. By simulating a U-shape ventilation network, t he air volume distribution and wind velocity in different sections of the model were measured and compared with practical data obtained in Vilafruns mine. Results show that the lowest wind velocity in the model is higher than 0.42 m/s, thus it is in a turbulent f low state, which satisfies the kinematical and dynamic similarity principles. T he characteristic of air volume distribution and wind velocity in Vilafruns mine are basically simulated by the experimental model through the obtained data and figures, which reflects the establishment of the model is correct and successful, and the experimental data is accurate and reliable. Moreover, this model provides useful references for the selection of mine ventilation types and for the optimization of the existing ventilation network.


Author(s):  
C T Twort ◽  
I S Lowndes ◽  
S J Pickering

The extraction of minerals and coal at greater depth, employing higher-powered machinery to improve production levels, imposes an increased burden on the ability of a ventilation system to maintain an acceptable mine climate. Hence, mechanical mine cooling systems are often adopted, which can be expensive both in terms of their associated capital and operating costs. Consequently, in order to optimize the costs it is essential to provide the mine operator with a method with which to determine the most cost effective and efficient mine cooling system. The following paper overviews the development of a novel approach to the energy analysis of mine cooling systems using the concepts of thermal exergy analysis. Generic model mine ventilation networks are constructed and the subsurface environments of these mine networks predicted. Models of various cooling system methods are developed and applied to control the underground climate within these mine networks to within pre-set climatic limits. The exergy transfers that are produced by the application of the different cooling methods are compared using performance indices. Models to represent chilled water distribution networks, used to supply the air coolers within the various cooling systems, are designed and balanced. The results of the exergy analyses applied to the operation of the various chilled water pipe networks are discussed and used to assess the exergetic performance of the application of each cooling system to the mine ventilation network.


Author(s):  
M.D. Popov ◽  
◽  
D.S. Kormshchikov ◽  
M.A. Semin ◽  
L.Yu. Levin ◽  
...  

Underground fires are one of the most serious emergencies that occur during mining operations. Analysis of possible scenarios for its development is a mandatory measure when designing new mine workings and when developing a plan for immediate elimination of accidents at the existing mine workings. The main danger that an underground fire creates for the mine ventilation system is a change in the ventilation mode and, accordingly, a change in the direction of movement of the air and harmful gases released during combustion. It is almost impossible to calculate in manual mode all the possible scenarios for the development of an emergency for different places where underground fires occur. This confirms the need to develop algorithms for automated assessment of the effect of thermal depression from a fire on the stability of the air flow in all mine workings of the mine ventilation network. The authors consider two numerical algorithms implemented in the «Aeroset» analytical complex and solving two independent problems. The first of them is determining the air flow stability in the mine on the whole in the presence of a fire of a given heat emission rate in any place of the mine working. The second task is to find the critical rate of fire heat generation in stationary workings, leading to a loss of stability of the air flow in the mined-out spaces of the mine. The techniques of increasing the speed of calculations of algorithms are studied. The article also describes the developed tools for graphical analysis of the calculation results. Examples of using such tools in practice are given. It is concluded that the developed software tools allow to quickly model the stability of air distribution in the mine ventilation networks of arbitrary topology in the presence of underground fires, and conveniently visualize the calculations.


2019 ◽  
Vol 109 ◽  
pp. 00012 ◽  
Author(s):  
Tetiana Bunko ◽  
Maksym Shyshov ◽  
Oleksandr Bokii ◽  
Anatolii Belikov ◽  
Oleksandr Zhalilov ◽  
...  

The increase of energy efficiency of main fans (MF) work is the basic condition of perfecting the mine ventilation system. During realization of multi-fan ventilation there is the non-productive «overbalancing» of vent flow from a weaker towards more powerful ventilator which causes decline of work efficiency of both. The questions of reducing the MF mutual influence on the outgoing air flow and increasing the aerodynamic quality of vent network have been studied and considered insufficiently. It is proposed to use the method of calculating the effective MF operating conditions taking into account the mutual influence of MF and areas-users of fresh air in mine ventilation network and on the basis of criterion of estimating the MF mutual influence, which will allow to enhance the energy efficiency of mine ventilation and labour safety of subsurface miners.


Author(s):  
Wacław Dziurzyński ◽  
Andrzej Krach ◽  
Teresa Pałka

This paper presents a methodology for determining the sensitivity of the main air flow directions in ventilation subnetworks to changes of aerodynamic resistance and of air density in mine workings. Formulae for determination of the sensitivity of the main subnetwork air flows by establishing the degree of dependency of the air volume stream in a given working on the variations in resistance or air density of other workings of the network have been developed. They have been implemented in the VentGraph mine ventilation network simulator. This software, widely used in Polish collieries provides an extended possibility to predict the process of ventilation, air distribution and, in the case of underground fire, also the spread of combustion gasses. The new method facilitates assessment by mine ventilation services of the stability of ventilation systems in exploitation areas and determine of the sensitivity of the main subnetwork air flow directions to changes of aerodynamic resistance and air density. Recently in some Polish collieries new longwalls are developed in seams located deeper then the bottom of the intake shaft. Such solution is called “exploitation below the level of access” or “sublevel”. The new approach may be applied to such developments to assess the potential of changes of direction and air flow rates. In addition, interpretation of the developed sensitivity indicator is presented. While analyzing air distributions for sublevel exploitation, application of current numerical models for calculations of the distribution results in tangible benefits, such as the evaluation of the safety or risk levels for such exploitation. Application of the VentGraph computer program, and particularly the module POŻAR (fire) with the newly developed options, enables an additional approach to the sensitivity indicator in evaluating air flow safety levels for the risks present during exploitation below the level of the intake shaft. The analyses performed and examples presented enabled useful conclusions in mining practice to be drawn.


2014 ◽  
Vol 962-965 ◽  
pp. 1095-1099
Author(s):  
Yu Wang

Based on the analysis of network theory and the airflow abnormal value of mine ventilation, the concept of sensitivity was introduced and a mathematical model to analyze the reason for the airflow abnormal values so as to realize the analysis for the airflow in all kinds of tunnels of ventilation system was put forward. By doing that, various reasons for the airflow abnormal value could be found so that possible predictions for the safety consequences could be made accordingly.


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